Examine source code of Green Leaves two

{
  "manifest_version": 2,
  "version": "1.0",
  "name": "green leaves two",
  "theme": {
    "images": {
      "additional_backgrounds": [
        "images/0.jpg"
      ]
    },
    "properties": {
      "additional_backgrounds_alignment": [
        "right bottom"
      ],
      "additional_backgrounds_tiling": [
        "repeat"
      ]
    },
    "colors": {
      "toolbar": "rgb(255, 255, 255)",
      "toolbar_text": "rgb(53, 140, 59)",
      "frame": "rgb(142, 179, 201)",
      "tab_background_text": "rgb(255, 255, 255)",
      "toolbar_field": "rgb(255, 255, 255)",
      "toolbar_field_text": "rgb(66, 67, 81)",
      "tab_line": "rgb(83, 150, 238)",
      "popup": "rgb(255, 255, 255)",
      "popup_text": "rgb(39, 40, 45)",
      "tab_loading": "rgb(83, 150, 238)"
    }
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{254b97d1-07cd-40e7-9fa7-db834dbd25a4}"
    }
  }
}